During the past several years, the popularity and viability of fuel cells for producing both large and small amounts of electricity has increased significantly. Fuel cells use an electrochemical reaction with reactants such as hydrogen and oxygen to produce electricity and heat. Fuel cells are similar to batteries except that fuel cells can be “recharged” while providing power. In addition, fuel cells are cleaner than other sources of power, such as devices that combust hydrocarbons.
Fuel cells provide a direct current (DC) that may be used to power motors, lights, computers, or any number of electrical appliances. A typical fuel cell includes an electrolyte disposed between two electrodes: an anode and a cathode. There are several different types of fuel cells, each having a different chemistry. Fuel cells are usually classified into one of five groups by the type of electrolyte used: proton exchange membrane (PEM) fuel cells, alkaline fuel cells (AFC), phosphoric-acid fuel cells (PAFC), solid oxide fuel cells (SOFC), and molten carbonate fuel cells (MCFC).
When an oxidant such as air is fed to the cathode, the cathode uses the oxidant to supply oxygen ions to the electrolyte. A fuel such as hydrogen or methane is also fed to the anode where it is transported to the electrolyte to react with the oxygen ions. This electrochemical reaction liberates electrons, which are then introduced into an external circuit to provide useful power.
Fuel cell systems typically require large quantities of cathode air to support the electrochemical processes. This air is typically drawn from the ambient environment. However, if ambient dust and dirt are also ingested into the fuel cell, these contaminants have detrimental effects on the system. To avoid these effects, filters are typically installed on the air intake for the cathode air stream. These filters typically require regular replacement in order to be effective.
Specifically, if the air filter is not regularly replaced, it may adversely affect the operation of the system's “air movers,” the devices that draw air from the ambient environment and provide air to the fuel cell. These devices are known as ‘air movers.’ These air movers are typically capable of generating only small amounts of pressure to overcome head losses associated with the system, which includes, but is not limited to, clogging in the air filter. To complicate the matter, flow geometry in some systems is often designed to be small in an attempt to miniaturize the system. A small flow geometry increases the pressure drop of the system and thus makes the pressure drop budget of the overall system a premium.
While needed for operation of the system, the use of a filter is also one obstacle to consumer compatible solutions because of the additional maintenance required. As mentioned, filters must be regularly maintained or replaced in order to prevent build-up on the filter from interfering with the air movers' ability to provide adequate air pressure to the fuel cell system. For the user, this would an inconvenience as it requires another item that must be provided and maintained in order to use the product. For the user that neglects the system and does not replace the filter, the pressure drop would increase and jeopardize the proper functioning of the system.